android - 当应用程序进入后台时服务停止

Question

您好，我在项目中使用 SignalR 进行聊天通信。聊天通信工作正常但是当应用程序进入后台时服务停止我需要完全运行服务直到我的应用程序被删除

这是我的服务代码

public class SignalRService extends Service {
private HubConnection mHubConnection;
private HubProxy mHubProxy;
private Handler mHandler; // to display Toast message
private final IBinder mBinder = new LocalBinder(); // Binder given to clients

public SignalRService() {
}

@Override
public void onCreate() {
    super.onCreate();
    mHandler = new Handler(Looper.getMainLooper());
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    int result = super.onStartCommand(intent, flags, startId);
    startSignalR();
    return result;
}

@Override
public void onDestroy() {
    Log.i("onDestroy","onDestroy");
    mHubConnection.stop();
    super.onDestroy();
}

@Override
public IBinder onBind(Intent intent) {
    // Return the communication channel to the service.
    startSignalR();
    return mBinder;
}

/**
 * Class used for the client Binder.  Because we know this service always
 * runs in the same process as its clients, we don't need to deal with IPC.
 */
public class LocalBinder extends Binder {
    public SignalRService getService() {
        // Return this instance of SignalRService so clients can call public methods
        return SignalRService.this;
    }
}

/**
 * method for clients (activities)
 */
public void sendMessage(String message) {
    String SERVER_METHOD_SEND = "Send";
    mHubProxy.invoke(SERVER_METHOD_SEND, message);
}

/**
 * method for clients (activities)
 */
public void sendMessage_To(String receiverName, String message) {
    String SERVER_METHOD_SEND_TO = "SendChatMessage";
    mHubProxy.invoke(SERVER_METHOD_SEND_TO, receiverName, message);
}

private void startSignalR() {
    Platform.loadPlatformComponent(new AndroidPlatformComponent());
    Credentials credentials = new Credentials() {
        @Override
        public void prepareRequest(Request request) {
            request.addHeader("User-Name", "BNK");
        }
    };

    String serverUrl = "http://10.10.10.180/signalr/hubs";
    mHubConnection = new HubConnection(serverUrl);
    mHubConnection.setCredentials(credentials);
    String SERVER_HUB_CHAT = "ChatHub";
    mHubProxy = mHubConnection.createHubProxy(SERVER_HUB_CHAT);
    ClientTransport clientTransport = new ServerSentEventsTransport(mHubConnection.getLogger());
    SignalRFuture<Void> signalRFuture = mHubConnection.start(clientTransport);

    try {
        signalRFuture.get();
    } catch (InterruptedException | ExecutionException e) {
        Log.e("SimpleSignalR", e.toString());
        return;
    }

    sendMessage("Hello from BNK!");

    String CLIENT_METHOD_BROADAST_MESSAGE = "broadcastMessage";
    mHubProxy.on(CLIENT_METHOD_BROADAST_MESSAGE,
            new SubscriptionHandler1<CustomMessage>() {
                @Override
                public void run(final CustomMessage msg) {
                    final String finalMsg = msg.UserName + " says " + msg.Message;
                    // display Toast message
                    mHandler.post(new Runnable() {
                        @Override
                        public void run() {
                            Log.i("message","message: "+finalMsg);
                            Toast.makeText(getApplicationContext(), finalMsg, Toast.LENGTH_SHORT).show();
                        }
                    });
                }
            }
            , CustomMessage.class);
}}

这是 Activity 代码

public class MainActivity extends AppCompatActivity {

private final Context mContext = this;
private SignalRService mService;
private boolean mBound = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Intent intent = new Intent();
    intent.setClass(mContext, SignalRService.class);
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}

@Override
protected void onStop() {
    // Unbind from the service
    Log.i("onStop","onStop");
    if (mBound) {
        unbindService(mConnection);
        mBound = false;
    }
    super.onStop();
}

public void sendMessage(View view) {
    if (mBound) {
        // Call a method from the SignalRService.
        // However, if this call were something that might hang, then this request should
        // occur in a separate thread to avoid slowing down the activity performance.
        EditText editText = (EditText) findViewById(R.id.edit_message);
        EditText editText_Receiver = (EditText) findViewById(R.id.edit_receiver);
        if (editText != null && editText.getText().length() > 0) {
            String receiver = editText_Receiver.getText().toString();
            String message = editText.getText().toString();
            mService.sendMessage_To(receiver, message);
            mService.sendMessage(message);
        }
    }
}

/**
 * Defines callbacks for service binding, passed to bindService()
 */
private final ServiceConnection mConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName className,
                                   IBinder service) {
        // We've bound to SignalRService, cast the IBinder and get SignalRService instance
        SignalRService.LocalBinder binder = (SignalRService.LocalBinder) service;
        mService = binder.getService();
        mBound = true;
    }

    @Override
    public void onServiceDisconnected(ComponentName arg0) {

        Log.i("onServiceDisconnected","onServiceDisconnected");

        mBound = false;
    }
};}

我的服务 list 代码

<service
        android:name=".SignalRService"
        android:enabled="true"
        android:exported="true" >
    </service>

请帮我解决这个问题

Answer 1

如果您将服务与任何组件绑定(bind)，如果没有其他客户端与之绑定(bind)，系统将自动销毁该服务。

如果你想独立运行一个服务，那么你必须启动一个服务而不是绑定(bind)。但是，如果您使用 startService()

启动服务，则无法与该服务通信

有关更多详细信息，请参阅文档 here